Tardigrades Use Intrinsically Disordered Proteins to Survive Desiccation

Genes upregulated during drying were identified, and the proteins they encode expressed in yeast and bacteria — organisms that do not normally survive desiccation — to test whether the proteins alone confer tolerance. Their behaviour on drying was characterised directly.

Studied in

Hypsibius exemplaris, Ramazzottius varieornatus

Sample size

gene expression analysis plus heterologous expression assays

Tardigrade-specific intrinsically disordered proteins are strongly induced by drying. On desiccation they vitrify, forming a glass-like solid that holds cellular structures in place. Expressing these proteins in yeast and bacteria conferred substantially improved desiccation tolerance on organisms that otherwise lack it.

• Improved tolerance in yeast is substantial but far below tardigrade levels; other components are involved.
• Two species, and different tardigrade lineages use partly different protein sets.
• Vitrification is characterised in vitro; direct observation inside a drying tardigrade is limited.

• Moving the survival machinery into yeast

  What actually protects a tardigrade as it dries out?

• Moving the mechanism into an organism that lacked it

  Tardigrades contain unusual proteins when they dry. Are those proteins doing the protecting, or merely present in an animal that protects itself some other way?

• Tardigrade

  Drying out, it sets into glass — and the glass is why the heat limit is where it is

• Tardigrade

  A tardigrade protein physically shields DNA, and it works in human cells too

• Desiccation tolerance

  The danger in drying out is not thirst. Water holds membranes and proteins in shape, and when it leaves they collapse. Organisms that survive it fill the gap with sugars or proteins that set into a glass.